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We have developed a new type of hybrid-structured Photonic Crystal Fiber (H-PCF) that includes a sectored core-cladding configuration. It's composed of a cladding with a regular circular sectored lattice structure and a core with a hexagonal sectored lattice structure. To extensively design, analyze, and calculate the fiber's properties, the finite element method has been used. The results provide validation for the superior performance of this novel fiber design. It simultaneously achieves extremely low effective material loss and confinement loss equal to 0.0145 cm⁻1 and 1 × 10⁻14 cm⁻1, respectively, at the 1 THz frequency. Furthermore, the fiber demonstrates nearly zero flattened dispersion (− 0.45 ± 0.55 ps/THz/cm) across the 0.9–1.3 THz frequency range, along with important attributes such as a large core power fraction (50%) and an effective area of 5 × 105 µm2. The suggested PCF design is practical for manufacturing utilizing currently available technologies. Moreover, the proposed PCF design, employing common structured regions in the circular and hexagonal patterns for the sectored cladding and core regions, respectively, is feasible for fabrication using existing technologies. Overall, this H-PCF shows significant potential for various THz applications, especially in THz wave guidance. [ABSTRACT FROM AUTHOR]

Variation of gate sidewall angle in V-shaped gate HEMTs impacts the device electrical performance, including self-heating effects, high-frequency operation and the breakdown electric field. In this paper, the influence of θ on the electrical characteristics of a nanoscale V-shaped gate HEMT is investigated. The electrical characteristics of the device are calculated as a function of gate sidewall angle to predict an appropriate θ which yields optimum performance. Our results reveal that although smaller sidewall angles allow for a higher device maximum operating temperature by improving self-heating effects, they render a smaller breakdown voltage and have a negligible effect on the drain current as well as the threshold voltage. Furthermore, reducing the sidewall angle deteriorates the device cut-off frequency by increasing the gate-source and gate-drain capacitances. This study underscores the fundamental role of the appropriate gate sidewall angle on device performance. [ABSTRACT FROM AUTHOR]

We propose a new generation of unbiased (biasfree) antenna-less CW THz photomixer emitters array made of asymmetric MSM gratings with subwavelength pitch, operating in optical nearfield regime. We take advantage of the size effects in near-field optics and electrostatics to demonstrate the possibility of enhancing the THz power by four orders of magnitude, as compared with a similar array of the same size that operates in the far-field regime. We show that with an appropriate choice of grating parameters in such THz sources the first plasmonic resonant cavity mode in nano-slit between two adjacent MSM can enhance the optical near-field absorption and hence the photo carriers' generation under the slit in the active medium. These photo carriers, on the other hand, are accelerated by the large built-in electric field sustained under the nano-slits by two dissimilar Schottky barriers to create the desired large THz power that is mainly radiated downward. A hybrid numerical simulation method is used to model and analyze these phenomena. [ABSTRACT FROM AUTHOR]